空指针异常

Question

public class IUserDao {

public boolean find(String name,String password) throws Exception{

 Connection conn = null;

 PreparedStatement st = null;

        ResultSet rs =null;

         try{

           conn = DbUtils.getConn();

           String sql = "select * from User where name=? and password=?";

           st = conn.prepareStatement(sql);

           st.setString(1, name);

           st.setString(2, password);

           rs = st.executeQuery();

  

       }catch (Exception e) {

            

       }

         System.out.println(rs);

if(rs.next()){

System.out.println("没有记录");

return false;

}

else{

System.out.println("登录成功");

return true;

}

}

public static void main(String args[]) throws Exception{

IUserDao ud=new IUserDao();

ud.find("admin", "12345d6");

}

}

其他类调用这个find 方法时，

java.lang.NullPointerException

at dao.IUserDao.find(IUserDao.java:36)

    ...

    ....